1. Field of the Invention
The present invention relates to a content providing system, and particularly relates to a system for providing a content key to a content reproducing device which decrypts content encrypted with the content key and reproduces the content.
2. Description of the Related Art
In recent years there has been an increase in unauthorized distribution and sharing of digital content such as music content and so forth, without permission of the copyright holder, as the Internet has become more commonplace and the speed and capacity of PCs (personal computers) has increased. Accordingly, copyright-protection technology for restricting distribution and usage of contents is spreading, to prevent such unauthorized acts.
For example, Japanese Unexamined Patent Application Publication No. 2002-359616 discloses copyright-protection technology wherein a license necessary for permitting usage of contents is provided to a device owned by a user, thereby restricting reproduction of contents, enabling sharing of contents, and so forth. This copyright-protection technology enables a user who has purchased the contents to share the contents among equipment owned by the user with a certain degree of freedom, while protecting the copyright of the contents. This also involves setting an expiration date on usage of the contents, the number of times that copying is permitted, the number of times that check-out is permitted, or the like, thereby establishing usage conditions of the contents corresponding to the license.